A laboratory is being set up for analysis of balance. This will enable simultaneous study of body angles, foot-floor forces and multiple EMGs. We hope to identify normal mechanisms of balance and how these are deranged in patients. The study of motor control in hemiplegia is being set up as the major project of the Unit. Patients with discrete brain lesions will be studied; patients with strokes will be the main group, and many patients will be followed serially from onset of the disorder to recovery. We hope to discover pathophysiological mechanisms including those mechanisms underlying recovery. Methods of study will include (1) quantitative clinical battery, (2) evoked potentials, (3) pre-motor potentials, (4) stretch reflexes, (5) EMG analysis of voluntary movements, and (6) PET scanning during voluntary movement.